Files
amc/docs/claude-jsonl-reference
teernisse 781e74cda2 docs(jsonl): add comprehensive Claude JSONL session log reference
Create authoritative documentation suite for Claude Code JSONL session
log processing, synthesized from codebase analysis, official Anthropic
documentation, and community tooling research.

Documentation structure (docs/claude-jsonl-reference/):

01-format-specification.md (214 lines):
- Complete message envelope structure with all fields
- Content block types (text, thinking, tool_use, tool_result)
- Usage object for token reporting
- Model identifiers and version history
- Conversation DAG structure via parentUuid

02-message-types.md (346 lines):
- Every message type with concrete JSON examples
- User messages (string content vs array for tool results)
- Assistant messages with all content block variants
- Progress events (hooks, bash, MCP)
- System, summary, and file-history-snapshot types
- Codex format differences (response_item, function_call)

03-tool-lifecycle.md (341 lines):
- Complete tool invocation to result flow
- Hook input/output formats (PreToolUse, PostToolUse)
- Parallel tool call handling
- Tool-to-result pairing algorithm
- Missing result edge cases
- Codex tool format differences

04-subagent-teams.md (363 lines):
- Task tool invocation and input fields
- Subagent transcript locations and format
- Team coordination (TeamCreate, SendMessage)
- Hook events (SubagentStart, SubagentStop)
- AMC spawn tracking with pending spawn registry
- Worktree isolation for subagents

05-edge-cases.md (475 lines):
- Parsing edge cases (invalid JSON, type ambiguity)
- Type coercion gotchas (bool vs int in Python)
- Session state edge cases (orphans, dead detection)
- Tool call edge cases (missing results, parallel ordering)
- Codex-specific quirks (content injection, buffering)
- File system safety (path traversal, permissions)
- Cache invalidation strategies

06-quick-reference.md (238 lines):
- File locations cheat sheet
- jq recipes for common queries
- Python parsing snippets
- Common gotchas table
- Useful constants
- Debugging commands

Also adds CLAUDE.md at project root linking to documentation and
providing project overview for agents working on AMC.

Sources include Claude Code hooks.md, headless.md, Anthropic Messages
API reference, and community tools (claude-code-log, claude-JSONL-browser).

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
2026-02-28 00:48:55 -05:00
..

Claude JSONL Session Log Reference

Comprehensive documentation for parsing and processing Claude Code JSONL session logs in the AMC project.

Overview

Claude Code stores all conversations as JSONL (JSON Lines) files — one JSON object per line. This documentation provides authoritative specifications for:

  • Message envelope structure and common fields
  • All message types (user, assistant, progress, system, summary, etc.)
  • Content block types (text, tool_use, tool_result, thinking)
  • Tool call lifecycle and result handling
  • Subagent spawn and team coordination formats
  • Edge cases, error handling, and recovery patterns

Documents

Document Purpose
01-format-specification.md Complete JSONL format spec with all fields
02-message-types.md Every message type with concrete examples
03-tool-lifecycle.md Tool call flow from invocation to result
04-subagent-teams.md Subagent and team message formats
05-edge-cases.md Error handling, malformed input, recovery
06-quick-reference.md Cheat sheet for common operations

File Locations

Content Location
Claude sessions ~/.claude/projects/<encoded-path>/<session-id>.jsonl
Codex sessions ~/.codex/sessions/**/<session-id>.jsonl
Subagent transcripts ~/.claude/projects/<path>/<session-id>/subagents/agent-<id>.jsonl
AMC session state ~/.local/share/amc/sessions/<session-id>.json
AMC event logs ~/.local/share/amc/events/<session-id>.jsonl

Path Encoding

Project paths are encoded by replacing / with - and adding a leading dash:

  • /Users/taylor/projects/amc-Users-taylor-projects-amc

Key Principles

  1. NDJSON format — Each line is complete, parseable JSON
  2. Append-only — Sessions are written incrementally
  3. UUID linking — Messages link via uuid and parentUuid
  4. Graceful degradation — Always handle missing/unknown fields
  5. Type safety — Validate types before use (arrays vs strings, etc.)

Sources